Enhancing the functional properties of acetylated hemicellulose films for active food packaging using acetylated nanocellulose reinforcement and polycaprolactone coating

CITATION: Mugwagwa, L. R. & Chimphango, A. F. A. 2020. Enhancing the functional properties of acetylated hemicellulose films for active food packaging using acetylated nanocellulose reinforcement and polycaprolactone coating. Food Packaging and Shelf Life, 24. doi:10.1016/j.fpsl.2020.100481The original publication is available at https://www.sciencedirect.com/journal/food-packaging-and-shelf-lifeAcetylated hemicellulose (AH)-nanocellulose (ACNC) films coated with polycaprolactone (PCL) films, were evaluated as active packaging for aqueous, alcoholic, fatty and acidic food. The effects of nanocellulose loading (0–50 %), degree of acetylation (DS) (0–2.34) and polycaprolactone coating (0.3 g/mL) on hydrophobicity and solubility of AH films in food simulants, were investigated. In addition, AH-CNC/PCL films were doped with polyphenols and their antioxidant release (temperature 5 °C–40 °C, time - 48 h) into food simulants was evaluated experimentally and by modelling (Migratest software). Increasing ACNC DS and loading, combined with a PCL coating increased films’ hydrophobicity (24.59° to 82.48°) and reduced film solubility in all the simulants (∼82.8 %). The release of polyphenols by the films was highest and best predicted using Migratest software for the fatty food simulant. Therefore, these films can be used as active packaging for fatty foods. Furthermore, Migratest modelling can be used to predict film performance during film design.https://www.sciencedirect.com/science/article/pii/S221428941930496XPublishers versio

Diffusion channel system for controlled atmosphere storage of spinach

Advanced research in Controlled/Modified Atmosphere storage systems has shown that open channels of different lengths and cross sectional areas, connected to an air tight storage chamber, are able to maintain variable stable gas concentrations which could be near optimal concentrations for CA/MA storage of various commodities.This study was geared towards assessing the suitability of the diffusion channels in maintaining a desired gas concentration for CA storage of spinach. Initially, the respiratory behaviour of spinach was studied in gas sealed chambers (replicated four times) stored at four different temperatures, 2$sp circ$C, 8$sp circ$C, 15$sp circ$C and 23$sp circ$C. The respiration rate of spinach was 20 mgCO$sb2$/kg.h, 66 mgCO$sb2$/kg.h, 163 mgCO$sb2$/kg.h and 271 mgCO$sb2$/kg.h for 2$sp circ$C, 8$sp circ$C, 15$sp circ$C and 23$sp circ$C, respectively. A model was developed based on principles of enzymatic kinetics which could reliably predict the respiration rate of spinach at any given storage temperature.Two other sets of experiments were carried in a cold room set at 2$sp circ$C. (Abstract shortened by UMI.

Effect of Integrating Xylan Extraction from E. grandis into the Kraft Pulping Process on Pulp Yield and Chemical Balance

Kraft mills have the potential to pre-extract hemicellulose from wood as another value added product. The impacts of pre-extracting xylan on pulp and handsheet properties, sodium and sulfur balances, and chemical make-ups in the kraft pulping process of Eucalyptus grandis were assessed. Xylan extractions using white liquor, green liquor, and NaOH were done under varying extraction times, temperatures, and alkaline concentrations; residues were subsequently pulped at 170 °C for 45 min. The highest xylan yield (15.15% w/w) was obtained with 2 M NaOH, at 120 °C for 90 min followed by white liquor (13.27% w/w), utilizing 20% AA at 140 °C for 90 min. Green liquor extraction with 2% total titratable alkali (TTA), at 160 °C and an H-factor of 800 produced the lowest yield (7.83% w/w). However, the green liquor extractions were the most practical for integration into the kraft process due to their limited effect on pulp yield and properties of handsheets produced from the pre-extracted woodchips and the sulfur and sodium make-up increase. White liquor extractions would favour high pulp yield with low kappa number and reduced chemical charge and cooking time. These results are important for technical-economic assessment of integrated kraft pulp biorefineries

Bioenergy and African transformation

CITATION: Lynd, L. R. et al. 2015. Bioenergy and African transformation. Biotechnology for Biofuels, 8(18): doi:10.1186/s13068-014-0188-5.The original publication is available at http://www.biotechnologyforbiofuels.com/content/8/1/18Among the world’s continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures.Publishers' Versio